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A close-up of a cheesy sausage and egg breakfast casserole in a glass dish with a serving scooped out.

Hearty Omelette Hashbrown Casserole

This satisfying Omelette Hashbrown Casserole combines crispy hashbrowns with a fluffy, cheesy egg mixture packed with savory ham and fresh vegetables, baked to golden perfection. It's the ultimate breakfast or brunch centerpiece!
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Prep Time 25 minutes
Cook Time 1 hour 5 minutes
Total Time 1 hour 30 minutes
Servings: 8 servings
Course: Breakfast, Brunch, Main Course
Cuisine: American
Calories: 410
Ingredients Equipment Method Notes

Ingredients
  

For the Hashbrown Layer
  • 2 lbs frozen shredded hashbrowns thawed completely and squeezed very dry
  • 1/4 cup unsalted butter melted
  • 1 tsp salt
  • 1/2 tsp black pepper
  • 1/2 tsp garlic powder
For the Omelette Filling
  • 1 tbsp olive oil
  • 1 cup diced cooked ham or cooked crumbled sausage/bacon
  • 1/2 cup diced yellow onion
  • 1/2 cup diced red bell pepper
  • 2 cups fresh spinach roughly chopped
  • 1 cup shredded sharp cheddar cheese
  • 1/2 cup shredded Monterey Jack cheese
For the Egg Mixture
  • 12 large eggs
  • 1/2 cup whole milk or half-and-half
  • 1 tsp salt
  • 1/2 tsp black pepper
  • 1/4 tsp dried mustard optional
For Topping and Garnish
  • 1/2 cup shredded sharp cheddar cheese for topping
  • 2 tbsp fresh chives or parsley chopped, for garnish (optional)

Equipment

  • 9x13 inch baking dish
  • Large mixing bowls
  • Large Skillet
  • Whisk
  • Spatula

Method
 

Prepare the Hashbrown Layer
  1. Preheat oven to 400°F (200°C). Lightly grease a 9x13 inch baking dish.
  2. In a large bowl, combine the thawed and thoroughly squeezed dry hashbrowns with melted butter, 1 tsp salt, 1/2 tsp black pepper, and garlic powder. Mix until evenly coated.
  3. Press the seasoned hashbrowns evenly into the bottom of the prepared baking dish, forming a firm layer. Bake for 20-25 minutes, or until the edges are golden brown and slightly crispy. Remove from oven and reduce temperature to 375°F (190°C).
Prepare the Omelette Filling
  1. While the hashbrowns are baking, heat olive oil in a large skillet over medium heat. Add diced ham, onion, and red bell pepper. Sauté for 5-7 minutes, until vegetables are softened.
  2. Add the chopped fresh spinach to the skillet and cook for another 2-3 minutes, until the spinach has wilted. Remove from heat and let cool slightly.
Assemble the Casserole
  1. In a separate large bowl, whisk together eggs, milk, 1 tsp salt, 1/2 tsp black pepper, and dried mustard (if using) until well combined.
  2. Stir the sautéed ham and vegetable mixture, 1 cup shredded cheddar cheese, and 1/2 cup shredded Monterey Jack cheese into the egg mixture.
  3. Pour the egg and filling mixture evenly over the pre-baked hashbrown layer in the baking dish.
Bake and Serve
  1. Bake in the preheated 375°F (190°C) oven for 35-40 minutes, or until the eggs are set and the casserole is lightly golden. During the last 5 minutes of baking, sprinkle the remaining 1/2 cup shredded cheddar cheese over the top and continue baking until melted and bubbly.
  2. Remove the casserole from the oven and let it rest for 10 minutes before slicing and serving. Garnish with fresh chopped chives or parsley, if desired.

Notes

For best results, ensure hashbrowns are thoroughly thawed and squeezed dry to prevent a watery casserole. You can prepare the vegetable and meat filling a day ahead and store it in the refrigerator. This casserole reheats well; cover and warm in the oven or microwave.